Problem with Database on host server

This is my code
public DataSet ExecuteDataset(string connectionString, CommandType commandType, string commandText)
{
DataSet ds = new DataSet();
using (MySqlConnection cn = new MySqlConnection(connectionString))
{
MySqlCommand cmd = new MySqlCommand(commandText, cn);
MySqlDataAdapter da = new MySqlDataAdapter(cmd);

try
{
da.Fill(ds);
}
catch (Exception ex)
{
errorDescription = ex.Message.ToString().Replace("\n", "");
string s = errorDescription.Substring(0, 6);
if (errorDescription.Substring(0, 6) == "#42000")
{
MySqlCommand cmd1 = new MySqlCommand("SET SQL_BIG_SELECTS = 1", cn);
try
{
cn.Open();
cmd1.ExecuteNonQuery();
da.Fill(ds);
}
catch (Exception)
{
errorDescription = ex.Message.ToString().Replace("\n", "");
SendToErrorPage(errorDescription);
}
finally
{
cmd1.Parameters.Clear();
cmd1.Dispose();
cn.Close();
}
}
else
{
SendToErrorPage(errorDescription);
}
}
finally
{
cmd.Parameters.Clear();
cmd.Dispose();
cn.Dispose();
}
}
replaceCorrectValues(ds);
return ds;

}

It open connection and executed the query very well but fail at time of filling data in dataset and gives posted error.

Thanks for reply, There was problem in connection string, It required port number of hosting, I solved this problem.